With rapid development on semiconductor manufacturing processes technology, feature size of semiconductor devices continues to shrink to meet the requirements for miniaturization, low power consumption, and high-degree-integration. As the feature size decreasing, light diffraction effect in photolithography becomes more and more obvious. This may generate dimension variation between the fabricated pattern and the designed mask and may degrade image fidelity. This phenomena is known as the Optical Proximity Effect (OPE). To compensate this OPE influence, a photolithography enhancement technique Optical Proximity Correction (OPC) is commonly used. During an OPC process, an OPC model may be developed to cancel the OPE influence. Then, the OPC model may be applied in the mask design process. Thus, the finally fabricated pattern may be much closer to the desired pattern, even when the OPE still exists, because the mask design process may already factor in the OPE influence.
However, in real scenarios, when forming certain structures with insulators in the substrate, the pattern on the surface of the substrate may still have some variations from the target patterns even after an OPC process. This may result in a poor quality of the fabricated semiconductor devices. The disclosed methods are directed to solve one or more problems set forth above and other problems.